加氯处理对再生水滴灌系统灌水器堵塞及性能的影响

Effect of chlorination on emitter clogging and system performance for drip irrigation with sewage effluent

选取有压力补偿功能和无压力补偿功能,标称流量1.0～2.6L/h的6种灌水器,研究了加氯间隔1～4周、系统余氯质量浓度2.5～10mg/L对二级处理再生水滴灌系统灌水器堵塞和系统均匀性的影响,以便确定加氯处理最优运行方式。系统采用每天灌溉12h的运行方式,累计运行84d(1008h)。结果表明,加氯处理可有效地减轻灌水器堵塞,使滴灌系统保持均匀系数大于90%的良好性能,流量小于1.38L/h的灌水器效果更为明显。尽管控制系统余氯浓度2.5、5.0和10.0mg/L均可以杀死再生水中99.9%的细菌,但加氯间隔1周和2周处理减轻堵塞使系统保持良好性能的效果优于加氯间隔4周的处理。从保持滴灌系统性能良好的角度出发,建议采用低浓度高频率的加氯处理运行方式。

The influences of chlorination schemes on emitter clogging and system performance of drip irrigation systems applying secondary effluent and groundwater were investigated to determine optimum chlorination practices.In the experiments,six types of emitters with or without a pressure-compensating device and having a nominal discharge rate ranging from 1.0 to 2.6 L/h were used and three intermittent injections that maintained the residual chlorine concentration of 2.5,5.0 and 10.0 mg/L at the end of the systems with an interval varying from one to four weeks were evaluated.The total duration of irrigation was 84 days,with a daily application of 12 hours.The results showed that all the chlorination schemes tested could effectively reduce the clogging in drip emitters applying sewage effluent,especially for the emitters with a nominal discharge rate of less than 1.38 L/h.A high system performance of statistical uniformity coefficient of greater than 90% could be obtained through intermittent chlorination.Although 99.9% of the total bacteria in the sewage effluent could be eliminated by the tested residual chlorine concentration of 2.5,5.0,and 10.0 mg/L,the injection intervals of one week or two weeks were found to be more effective than the intervals of four weeks in reducing clogging due to biological growth.To maintain a high system performance,a chlorination scheme with low-concentration injection at high frequency is recommended.